Salinity Province 71, Marnoo

The medium sized Marnoo Salinity Province is underlain by local to intermediate scale Groundwater Flow Systems (GFSs) in deeply weathered fractured Palaeozoic rocks overlain by a regional to intermediate scale GFS that covers the area from the Great Dividing Range in the south to Lake Buloke in the north. The area is an alluvial flood plain with extensive discharge areas developed on the shallower GFS, particularly at the junction of the Avon and Richardson Rivers. Broad scale flooding has a major impact on groundwater levels in the area and, coupled with existing shallow watertables, drives salinity discharge in low-lying areas. Groundwater levels monitored in the area since the 1980s and continuing today have illustrated an extensive, flat piezometric surface that shows strong flood impacted fluctuations.

The main salinity mitigation option implemented has been the planting of perenial pastures, although much of this has recently been cropped with cereal and legumes. Some significant remnant vegetation has been identified along the main rivers and has been added to with revegetation plantings.